use release 11 to comply with the plan

Signed-off-by: Lukas Jungmann <lukas.jungmann@oracle.com>

Author: lukasj

api/pom.xml

@@ -98,7 +98,7 @@
         <vendor.name>Eclipse Foundation</vendor.name>
         <implementation.vendor.id>org.glassfish</implementation.vendor.id>
 
-        <maven.compiler.release>21</maven.compiler.release>
+        <maven.compiler.release>11</maven.compiler.release>
     </properties>
 
     <build>